40 Questions
What is the result of the reaction between concentrated sulphuric(VI) acid and charcoal?
Production of carbon(IV)oxide
What is the effect of diluting concentrated sulphuric(VI) acid?
Decrease in the number of moles present in a given volume of solution
What is the purpose of adding acidified potassium dichromate(VI) solution to the filter paper?
To test for the presence of sulphur(IV)oxide
What is the type of reaction involved in the displacement of nitric(V) acid from its salt?
Displacement reaction
What is the role of concentrated sulphuric(VI) acid in the preparation of nitric(V) acid?
As a reactant
What is the effect of adding water to concentrated sulphuric(VI) acid?
The acid becomes less corrosive
What is the purpose of using acidified potassium dichromate(VI) solution?
To test for the presence of sulphur(IV)oxide
What is the result of the reaction between concentrated sulphuric(VI) acid and sulphur?
Production of sulphur(IV)oxide
What happens when hydrogen sulphide gas is passed through acidified potassium dichromate(VI) solution?
The solution turns green
What is the byproduct of the reaction between hydrogen sulphide gas and acidified potassium dichromate(VI) solution?
Yellow solid residue
What is the purpose of using acidified potassium dichromate(VI) solution in a chemical test?
To detect the presence of hydrogen sulphide gas
What happens when hydrogen sulphide gas is passed through acidified potassium manganate(VII) solution?
The solution turns colourless
What is the byproduct of the reaction between hydrogen sulphide gas and acidified potassium manganate(VII) solution?
Yellow solid residue
What is the purpose of using acidified potassium manganate(VII) solution in a chemical test?
To detect the presence of hydrogen sulphide gas
What happens when hydrogen sulphide gas is passed through bromine water?
The solution turns colourless
What is the byproduct of the reaction between hydrogen sulphide gas and bromine water?
Yellow solid residue
What is the result of the reaction between ZnCO3 and H2SO4?
ZnSO4 and H2O and CO2
Which of the following oxides forms a blue solution when reacted with dilute sulphuric acid?
CuO
What is the product of the reaction between ZnO and H2SO4?
ZnSO4 and H2O
What is the result of the reaction between Na2O and H2SO4?
Na2SO4 and H2O
What is the common product of the reaction between a metal oxide and dilute sulphuric acid?
H2O
Why do the reactions of calcium, lead and barium carbonates with dilute sulphuric acid stop after a while?
Because the sulphate salts formed coat the unreacted metal
What is the product of the reaction between 2NaOH and H2SO4?
Na2SO4 and H2O
Where does hydrogen sulphide occur naturally?
In volcanic areas
What is the product of the reaction between Mg(s) and H2SO4(aq)?
MgSO4(aq) + H2(g)
Which metal reacts explosively with dilute sulphuric acid?
Sodium
What happens when a metal carbonate or hydrogen carbonate is added to dilute sulphuric acid?
A sulphate salt is formed with the evolution of carbon dioxide gas
What is the colour of the solution formed when Iron(II)Carbonate is added to dilute sulphuric acid?
Green
What is the product of the reaction between Zn(s) and H2SO4(aq)?
ZnSO4(aq) + H2(g)
What is the purpose of introducing a burning splint on top of the boiling tube?
To test if the gas produced is flammable
What is the characteristic of the gas produced when a metal carbonate or hydrogen carbonate is added to dilute sulphuric acid?
It is colourless and extinguishes a burning splint
What is formed when carbon dioxide gas is bubbled in lime water?
A white precipitate
What is the product formed when Pb+(aq) reacts with H2S?
PbS
What is the colour of the precipitate formed when Cu2+(aq) reacts with H2S?
Black
What is formed when H2S(g) reacts with NaOH(l) in equimolar concentrations?
NaHS
What is the purpose of adding nitric(V) acid in the test for sulphates and sulphites?
To distinguish between SO42- and SO32- ions
What is the observation when the preserved sample is heated to boil?
The precipitate persists
What is the purpose of adding acidified potassium manganate(VII) to the preserved sample?
To distinguish between SO42- and Cl- ions
What is the observation when acidified potassium manganate(VII) is added to the preserved sample?
The precipitate dissolves
What is the final inference if the white precipitate persists on boiling?
Presence of SO42- ions
Study Notes
Reaction between Sulphuric Acid and Metals
- Sulphuric acid oxidizes non-metals to non-metallic oxides and reduces itself to sulphur(IV)oxide gas
- Charcoal is oxidized to carbon(IV)oxide, and sulphur is oxidized to sulphur(IV)oxide
- Chemical equation: C(s) + 2H2SO4(aq) --> CO2(aq) + 2SO2(g) + 2H2O(l)
- S(s) + 2H2SO4(aq) --> 3SO2(g) + 2H2O(l)
Displacement of Less Volatile Acids
- Concentrated sulphuric acid displaces more volatile acids from their salts
- Chemical equation: KNO3(s) + H2SO4(aq) --> KHSO4(l) + HNO3(g)
- Chemical equation: KCl(s) + H2SO4(aq) --> KHSO4(s) + HCl(g)
Properties of Dilute Sulphuric Acid
- Dilute sulphuric acid is made by adding concentrated sulphuric acid to distilled water
- Diluting concentrated sulphuric acid decreases the number of moles present in a given volume of solution, making the acid less corrosive
- Chemical equations:
- Mg(s) + H2SO4(aq) --> MgSO4(aq) + H2(g)
- Zn(s) + H2SO4(aq) --> ZnSO4(aq) + H2(g)
- Fe(s) + H2SO4(aq) --> FeSO4(aq) + H2(g)
Reaction with Metal Carbonates and Hydrogen Carbonates
- Effervescence occurs when a metal carbonate or hydrogen carbonate is added to dilute sulphuric acid
- Carbon(IV)oxide gas is produced, which extinguishes a burning splint and forms a white precipitate when bubbled in lime water
- Chemical equations:
- ZnCO3(s) + H2SO4(aq) --> ZnSO4(aq) + H2O(l) + CO2(g)
- CuCO3(s) + H2SO4(aq) --> CuSO4(aq) + H2O(l) + CO2(g)
- FeCO3(s) + H2SO4(aq) --> FeSO4(aq) + H2O(l) + CO2(g)
- 2NaHCO3(s) + H2SO4(aq) --> Na2SO4(aq) + 2H2O(l) + 2CO2(g)
Reaction with Metal Oxides and Hydroxides
- Metal oxides react with dilute sulphuric acid to form a salt and water
- Chemical equations:
- ZnO(s) + H2SO4(aq) --> ZnSO4(aq) + H2O(l)
- CuO(s) + H2SO4(aq) --> CuSO4(aq) + H2O(l)
- MgO(s) + H2SO4(aq) --> MgSO4(aq) + H2O(l)
- Na2O(s) + H2SO4(aq) --> Na2SO4(aq) + H2O(l)
Reaction with Hydrogen Sulphide
- Hydrogen sulphide gas reduces acidified potassium dichromate(VI) from orange Cr2O72- ions to green Cr3+ ions
- Hydrogen sulphide gas decolorizes acidified purple potassium manganate(VII) solution
- Hydrogen sulphide gas reduces red-brown bromine water to colourless hydrobromic acid (HBr)
This quiz is about the oxidation reaction of sulphur with concentrated sulphuric acid, producing sulphur dioxide gas and its characteristics.
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